Portable computers offer many great advantages to the user. A single portable computer can be used in place of several stationary computers in the home, office, and elsewhere. Data and computing power can easily be transported on the road or to a remote site. The problem of inconsistent data on remote unconnected computers can usually be avoided. The utility of these devices depends on the degree to which they are portable (their size and weight), on the degree with which they can reproduce the ergonomics of a full-sized computer, and on their durability. Early "credit-card" calculators were not durable. They were typically held in a wallet in the back pants pocket. The user sitting down invariably bent the card sufficiently to break the fragile and brittle display. Current laptop computers protect the fragile display with thick and heavy plastic "armor". This adds weight and size and therefore reduces portability. Current laptop computer design generally represents a compromise between the size as measured by the "footprint" of the folded device and the ergonomics. They are designed around the ergonomic constraint that the keyboard width should be roughly the width of two human hands (about ten inches).
Numerous patents have been awarded for the introduction and refinement of the folding display and keyboard (Lai-Fa Hsieh, Great Electronics Corporation, U.S. Pat. No. 4,926,365; Takashi Hosoi, Toshiba, U.S. Pat. No. 5,052,078, etc.). A recent article in the January 1994 issue of PC Laptop provides a detailed and comprehensive review of 86 handheld, pen-based, notebook, and laptop computing devices. Essentially all of the devices which use a keyboard have the display fold into the keyboard.
In these current designs, the footprint is constrained to be as large as the larger of the two components. Moreover, the keyboard has an aspect ratio of roughly two-to-one, whereas the standard displays have an aspect ratio close to unity; 640.times.480, 1280.times.1024 pixels are common values. The result of this inconsistency is wasted footprint area.
Laptop makers have gone to great lengths to work around this constraint. One design compresses the aspect ratio of the pixels so that each pixel is rectangular rather than square. This allows standard display resolutions to be displayed in elongated displays. However, the resultant images are distorted. Circular pie charts become elliptical.
An alternative design is incorporated into current subnotebooks and personal organizers. This design simply shrinks the keyboard substantially below the size that is ergonomically comfortable. Typically the overly packed keys must be curved in a convex manner to prevent inadvertent actuation of adjacent keys. These have been derisively termed "chicklets keyboards" by reviewers.
Personal information managers solve the problem by declaring that the keyboard is unnecessary and by promising useable voice and handwriting recognition capability sometime in the future.
One attempt to solve some of these problems uses hinged keyboards. See U.S. Pat. Nos. 3,940,758; 4,395,704; 4,517,660; 4,939,514. But these approaches all suffer their own shortcomings: the hinges protrude and interfere with the use of the keyboard; the display must be guarded and protected so it is unduly large and is generally fixed to the keyboard or other structure and does not collapse.